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numpy.core.defchararray.chararray.expandtabs
method
chararray.expandtabs(tabsize=8)[source]- 
    
Return a copy of each string element where all tab characters are replaced by one or more spaces.
See also
char.expandtabs 
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 https://docs.scipy.org/doc/numpy-1.16.1/reference/generated/numpy.core.defchararray.chararray.expandtabs.html